code: def test_styleof():
      styles = [
          (Basic, {"color": "blue", "shape": "ellipse"}),
          (Expr, {"color": "black"}),
      ]
      assert styleof(Basic(S(1)), styles) == {
          "color": "blue",
          "shape": "ellipse",
      }
  
      assert styleof(x + 1, styles) == {
          "color": "black",
          "shape": "ellipse",
      }
  
file_path: sympy/sympy/printing/tests/test_dot.py
imports: from sympy.printing.dot import purestr, styleof, attrprint, dotnode, dotedges, dotprint
  from sympy.core.basic import Basic
  from sympy.core.expr import Expr
  from sympy.core.numbers import Float, Integer
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol, symbols
  from sympy.printing.repr import srepr
  from sympy.abc import x
label_desc: Use image node_id 2 for calling a global function with example usage: test_styleof() without return types